Project Summary/Abstract Approximately 25-30% of the U.S. population will experience anxiety pathology severe enough to qualify for an anxiety disorder diagnosis during their lifetime. Critically, the majority will not receive treatment, creating a serious need to consider alternative approaches to delivering mental health services that can meet needs on a larger scale. Cognitive Bias Modification (CBM) interventions for anxiety hold considerable promise as a way to meet these needs. These programs alter biased ways of thinking, such as selective assignment of threat interpretations, which are known to cause and maintain anxiety. CBM for interpretation bias (CBM-I) has established efficacy when administered via computer in the laboratory, and there is clear evidence for target engagement (i.e., change in interpretations, the identified mechanism). Now, effectiveness needs to be tested in the community, using sufficiently large samples to evaluate key moderators of its effects, including delivery method (computer vs. mobile phone) and the addition of minimal human contact (for those at risk of attrition). Addressing attrition is critical given high rates of drop out for web-based interventions. The PI's lab is ideally positioned to test moderators of CBM-I. Specifically, via the PI's MindTrails web site (established with the lab's prior NIMH R34MH106770 award), the lab already has the infrastructure to deliver CBM to the public and recruit large anxious samples. Moreover, the PI and Co-I have established infrastructure to do mobile sensing of mood and CBM-I delivery via mobile phones. Thus, the project can respond to NIMH's request for ?Effectiveness trials that can contribute to advancing the personalization of mental health care.? The current proposal aims to compare effectiveness and target engagement of CBM-I delivered via computer vs. mobile phone, and test if adding minimal human contact for participants at risk of dropout improves retention and outcomes. Study 1 will provide a pilot feasibility and user experience test of the CBM-I program on mobile phones. Study 2 will examine the lab's current online, computer-based CBM-I data to help determine empirical indicators of attrition. Study 3 will provide the primary test of moderators of effectiveness. Namely, in Study 3, N=840 high anxious participants will be randomized to one of 3 conditions: 1) CBM-I training delivered by computer (at existing MindTrails site); 2) CBM-I training delivered by mobile phone; 3) Control group- Psychoeducation only. CBM-I conditions include 5 weekly training sessions. Based on theoretically- and empirically-derived predictors of attrition, participants identified as high-risk for dropout in conditions 1 and 2 will then be randomly assigned to add minimal human contact (using the TeleCoach protocol) or no change. Using this adaptive intervention, known as Sequential, Multiple Assignment, Randomized Trial (SMART), the project can test both the effects of CBM-I delivery method and the added value of human contact to improve retention for participants at high-risk for dropping out. !